#216 - enable break and continue within for loops (#222)

Co-Authored-By: Alvin Yan <aussiroth@users.noreply.github.com>
Co-Authored-By: Victor Loh <lohvht@users.noreply.github.com>

* #216 - experimenting with using signal variable
* #216 - possible solution found
use casper.bypass() to count how many steps to teleport to and bypass when a break statement is issued. nice catch @Aussiroth !
* #216 - use teleport marker
* #216 - use stricter matching conditions
* #216 - more complicated test
* #216 - cleaned up to work for break step
* #216 - initial implementation of continue
doesn't work but don't break existing break test case.
* #216 - working version of continue + break
* #216 - add infinity constant for looping
eg

for n from 1 to infinity
{
echo n
}

if constant too big, takes very large to build stack before execution. trade-off decided to be 1024

src/samples/loop_test

@@ -0,0 +1,6 @@
+for n from 1 to 10
+{
+	echo n
+	if n equals to 6
+	break;
+}

src/samples/loop_test2

@@ -0,0 +1,26 @@
+for n from 1 to 10
+{
+	echo n
+	if n equals to 6
+	{
+		for k from 80 to 85
+		{
+			echo k
+			if k equals to 83
+			{
+				break;
+			}
+		}
+	}
+}
+
+for cde from 1 to 5
+{
+	echo "cde " + cde
+}
+
+for abc from 1 to 5
+{
+	echo "abc " + abc
+}
+

src/samples/loop_test3

@@ -0,0 +1,35 @@
+for n from 1 to 10
+{
+	echo n
+	if n equals to 6
+	{
+		for k from 80 to 85
+		{
+			echo k
+			if k equals to 83
+			{
+				break;
+			}
+		}
+	}
+}
+
+for cde from 1 to 5
+{
+	echo "cde " + cde
+}
+
+for abc from 1 to 5
+{
+	echo "abc " + abc
+}
+
+for n from 30 to 35
+{
+	echo n
+}
+
+for k from 20 to 25
+{
+	echo k
+}

src/samples/loop_test4

@@ -0,0 +1,39 @@
+for n from 1 to 10
+{
+	echo n
+	if n equals to 6
+	{
+		for k from 80 to 85
+		{
+			echo k
+			if k equals to 83
+			{
+				break;
+			}
+		}
+	}
+}
+
+for cde from 1 to 5
+{
+	echo "cde " + cde
+	if cde equals to 3
+	break;
+}
+
+for abc from 1 to 5
+{
+	if abc equals to 3
+	break
+	echo "abc " + abc
+}
+
+for n from 30 to 35
+{
+	echo n
+}
+
+for k from 20 to 25
+{
+	echo k
+}

src/samples/loop_test5

@@ -0,0 +1,40 @@
+for n from 1 to 10
+{
+	echo n
+	if n equals to 6
+	{
+		for k from 80 to 85
+		{
+			continue
+			echo k
+			if k equals to 83
+			{
+				break;
+			}
+		}
+	}
+}
+
+for cde from 1 to 5
+{
+	echo "cde " + cde
+	if cde equals to 3
+	continue;
+}
+
+for abc from 1 to 5
+{
+	if abc equals to 3
+	continue
+	echo "abc " + abc
+}
+
+for n from 30 to 35
+{
+	echo n
+}
+
+for k from 20 to 25
+{
+	echo k
+}

src/samples/loop_test6

@@ -0,0 +1,6 @@
+for n from 1 to 10
+{
+if n equals to 5
+continue
+echo n
+}

src/samples/loop_test7

@@ -0,0 +1,5 @@
+echo infinity
+for n from 1 to infinity
+{
+echo n
+}

src/tagui_header.js

@@ -13,6 +13,9 @@ var automation_start_time = Date.now(); casper.echo('\nSTART - automation starte
 // initialise time for timer() function
 var timer_start_time = Date.now();
 
+// infinity constant for use in for loops
+var infinity = 1024;
+
 // initialise default global variables
 var quiet_mode = false; var save_text_count = 0; var snap_image_count = 0;
 
@@ -41,6 +44,19 @@ var r_result = ''; var r_json = {}; var py_result = ''; var py_json = {};
 var inside_py_block = 0; var inside_r_block = 0; var inside_run_block = 0;
 var inside_vision_block = 0; var inside_js_block = 0; var inside_dom_block = 0;
 
+// determine how many casper.then steps to skip
+function teleport_distance(teleport_marker) {number_to_hop = 0;
+if (teleport_marker.indexOf('[BREAK_SIGNAL]') > -1) {for (s = casper.steps.length-1; s >= 0; s--) {
+if (casper.steps[s].toString() == ("function () {for_loop_signal = '"+teleport_marker+"';}"))
+{number_to_hop = s; break;}};} // search backward direction for break step
+else if (teleport_marker.indexOf('[CONTINUE_SIGNAL]') > -1) {for (s = casper.step; s <= casper.steps.length-1; s++) {
+if (casper.steps[s].toString() == ("function () {for_loop_signal = '"+teleport_marker+"';}"))
+{number_to_hop = s; break;}}; // search forward direction for continue step
+if (number_to_hop == 0) {for (s = casper.steps.length-1; s >= 0; s--) {if (casper.steps[s].toString() == 
+("function () {for_loop_signal = '"+teleport_marker.replace('[CONTINUE_SIGNAL]','[BREAK_SIGNAL]')+"';}"))
+{number_to_hop = s; break;}};}} // handle as break if no step left to continue
+else return 0; if ((number_to_hop - casper.step) > 0) return (number_to_hop - casper.step); else return 0;}
+
 // techo function for handling quiet option
 function techo(echo_string) {if (!quiet_mode) { // mute about:blank, eg for desktop automation
 if ((echo_string == 'about:blank - \n') || (echo_string == '\nabout:blank - ')) casper.echo('');
@@ -777,11 +793,13 @@ if ((raw_intent.charAt(raw_intent.length-1) == '{') || (raw_intent.charAt(raw_in
 if ((raw_intent.substr(0,3) == 'if ') || (raw_intent.substr(0,4) == 'else')) return true;
 if ((raw_intent.substr(0,4) == 'for ') || (raw_intent.substr(0,6) == 'while ')) return true;
 if ((raw_intent.substr(0,7) == 'switch ') || (raw_intent.substr(0,5) == 'case ')) return true;
-if ((raw_intent.substr(0,6) == 'break;') || (raw_intent.substr(0,9) == 'function ')) return true;
+if ((raw_intent.substr(0,6) == 'break;') || (raw_intent == 'break')) return true;
+if ((raw_intent.substr(0,9) == 'continue;') || (raw_intent == 'continue')) return true;
 if ((raw_intent.substr(0,7) == 'casper.') || (raw_intent.substr(0,5) == 'this.')) return true;
 if (raw_intent.substr(0,7) == 'chrome.') return true; // chrome object for chrome integration
 if (raw_intent.substr(0,5) == ('test'+'.')) return true; // avoid replacement with test option
 if ((raw_intent.substr(0,2) == '//') || (raw_intent.charAt(raw_intent.length-1) == ';')) return true;
+if (raw_intent.substr(0,9) == 'function ') return true; // function definition
 // assume = is assignment statement, kinda acceptable as this is checked at the very end
 if (raw_intent.indexOf('=') > -1) return true; return false;}
 

src/tagui_parse.php

@@ -485,12 +485,13 @@ function is_code($raw_intent) {
 if ((substr($raw_intent,0,3)=="if ") or (substr($raw_intent,0,4)=="else")) return true;
 if ((substr($raw_intent,0,4)=="for ") or (substr($raw_intent,0,6)=="while ")) return true;
 if ((substr($raw_intent,0,7)=="switch ") or (substr($raw_intent,0,5)=="case ")) return true;
-if ((substr($raw_intent,0,6)=="break;") or (substr($raw_intent,0,9)=="function ")) return true;
+if ((substr($raw_intent,0,6)=="break;") or ($raw_intent=="break")) return true;
+if ((substr($raw_intent,0,9)=="continue;") or ($raw_intent=="continue")) return true;
 if ((substr($raw_intent,0,7)=="casper.") or (substr($raw_intent,0,5)=="this.")) return true;
 if (substr($raw_intent,0,7)=="chrome.") return true; // chrome object for chrome integration
 if (substr($raw_intent,0,5)=="test.") {$GLOBALS['test_automation']++; return true;}
 if (substr($raw_intent,0,2)=="//") {$GLOBALS['real_line_number']--; return true;} 
-if (substr($raw_intent,-1)==";") return true;
+if (substr($raw_intent,-1)==";") return true; if (substr($raw_intent,0,9)=="function ") return true;
 // assume = is assignment statement, kinda acceptable as this is checked at the very end
 if (strpos($raw_intent,"=")!==false) return true; return false;}
 
@@ -952,12 +953,14 @@ function parse_condition($logic) { // natural language handling for conditions
 else if (($code_block_intent == "for") and (substr($logic,0,1) == "{")) {
 $last_delimiter_pos = strrpos($GLOBALS['for_loop_tracker'],"|");
 $for_loop_variable_name = substr($GLOBALS['for_loop_tracker'],$last_delimiter_pos+1);
-$code_block_header = "(function (" . $for_loop_variable_name . ") { // start of IIFE pattern\n";}
+$code_block_header = "{casper.then(function() {for_loop_signal = '[CONTINUE_SIGNAL][".$for_loop_variable_name."]';});\n".
+"(function (" . $for_loop_variable_name . ") { // start of IIFE pattern\n";}
 
 else if (($code_block_intent == "for") and (substr($logic,0,1) == "}")) {
 $last_delimiter_pos = strrpos($GLOBALS['for_loop_tracker'],"|");
 $for_loop_variable_name = substr($GLOBALS['for_loop_tracker'],$last_delimiter_pos+1);
-$code_block_footer = "})(" . $for_loop_variable_name . "); // end of IIFE pattern\n";
+$code_block_footer = "})(" . $for_loop_variable_name . "); // end of IIFE pattern, with dummy marker for break step\n".
+"casper.then(function() {for_loop_signal = '[BREAK_SIGNAL][".$for_loop_variable_name."]';});}";
 $last_delimiter_pos = strrpos($GLOBALS['code_block_tracker'],"|");
 $GLOBALS['code_block_tracker']=substr($GLOBALS['code_block_tracker'],0,$last_delimiter_pos);
 $last_delimiter_pos = strrpos($GLOBALS['for_loop_tracker'],"|");
@@ -973,7 +976,6 @@ function parse_condition($logic) { // natural language handling for conditions
 else if (substr($logic,0,1) == "}") $logic = "} // end of code block\n".substr($logic,1)."\n".$code_block_footer."});\n";
 $logic = str_replace("\n\n","\n",$logic); // clean up empty lines from { and } processing
 
-
 // section 2 - natural language handling for conditions and loops 
 if ((substr($logic,0,3)=="if ") or (substr($logic,0,8)=="else if ")
 or (substr($logic,0,4)=="for ") or (substr($logic,0,6)=="while ")) {
@@ -1059,6 +1061,14 @@ function parse_condition($logic) { // natural language handling for conditions
 // then avoid async wait (casper.then/waitFor/timeout will hang casperjs/phantomjs??) 
 if (substr($logic,0,6)=="while ") $GLOBALS['inside_while_loop'] = 1; 
 
+// section 4 - to handle break and continue steps in for loops 
+if (($logic=="break") or ($logic=="break;"))
+{$teleport_marker = str_replace("|","",substr($GLOBALS['for_loop_tracker'],strrpos($GLOBALS['for_loop_tracker'],"|")));
+$logic = "casper.bypass(teleport_distance('[BREAK_SIGNAL][".$teleport_marker."]')); return;";}
+if (($logic=="continue") or ($logic=="continue;"))
+{$teleport_marker = str_replace("|","",substr($GLOBALS['for_loop_tracker'],strrpos($GLOBALS['for_loop_tracker'],"|")));
+$logic = "casper.bypass(teleport_distance('[CONTINUE_SIGNAL][".$teleport_marker."]')); return;";}
+
 // return code after all the parsing and special handling
 return $logic;}